Coccidioidomycosis, also known as Valley Fever, is a fungal disease caused by Coccidioides spp. that infects an estimated 150,000 people each year in the United States. Current diagnosis of coccidioidomycosis relies on detection of anti-coccidioidal antibodies in patient sera. However, the sensitivity of this serological assay is particularly low in the first few weeks of illness. A promising strategy to improve early diagnosis of Coccidioides infections is to detect specific protein antigens from Coccidioides which are shed into urine or serum. However, antigenuria/antigenemia-based diagnostic assays for coccidioidomycosis are not yet available, resulting in a critical need for the development of this type of diagnostic. The goal of this project is an immunoassay that will use serum or urine as a sample to diagnose coccidioidomycosis. Our overall hypothesis is that protein biomarker targets are shed into the urine or serum of Coccidioides-infected mice. The approach will be the use of scFv phage display technology to facilitate the identification of Coccidioides biomarkers in urine and serum from Coccidioides-infected mice. The product will be an immunoassay in the lateral flow assay (LFA) or enzyme immunoassay (EIA) format in order to facilitate earlier diagnosis of coccidioidomycosis. Criteria for success of this Phase I SBIR would be the identification and validation of at least one protein biomarker from the urine or serum of Coccidioides-infected mice. If the goals of this Phase I project are achieved, a Phase II application will use the protei biomarker(s) and/or antibody(s) generated from this Phase I project to construct and evaluate an immunoassay in LFA or EIA format. If successful, this translational research project could dramatically decrease the morbidity and health care costs associated with coccidioidomycosis through earlier diagnosis.